The word lunatic was coined in the 13th century and is derived from "luna," which is Latin for moon, according to the Online Etymology Dictionary, so it has long been thought there is a lunar influence on human behavior. Some recent studies seem to support this connection, and there are many first-hand accounts from professionals who believe strongly this is the case. Yet large scale analysis paints a different picture.

Impact on Sleep

The results of a study led by Christian Cajochen, published in the August 2013 issue of "Current Biology," suggest the lunar cycle modulates human sleep. Around the full moon, it took subjects 5 minutes longer to fall asleep, deep sleep was reduced by 30 percent as evidenced by decreased delta brain wave activity, and total sleep duration was reduced by 20 minutes. In the same year this study was published, the "Time" article "How the Moon Messes With Your Sleep" reported that Cajochen's study was originally done to see how age and gender influence sleep. Only years later did the researchers review the data to see if there was a lunar influence.

Influence on Alzheimer's Patients

At a conference sponsored by STTI -- a nonprofit, international honor society of nursing, Alan Beck of Purdue University reported the results of a behavioral study involving Alzheimer's patients. During the full moon, Alzheimer's patients displayed a significant increase in wandering, anxiety, physical aggression and verbal confrontation. The full moon also appeared to significantly affect the activities of daily living for the Alzheimer's patients.

Anecdotal Evidence, Beliefs

In a July 2013 News.com.au article, Dr. Gordian Fulde -- head of the emergency department at St. Vincent's Hospital in Darlinghurst, Sydney -- is quoted as saying people do indeed behave more strangely during a full moon. In the same article, Sydney psychologist Adam Fitzpatrick is quoted as saying he can predict which clients he'll see based on the size of the moon and that many patients are more emotionally distressed around the time of a full moon. These reports, however, may be due to "illusory correlation," a term coined by psychologists Loren and Jean Chapman. The 2009 "Scientific American" article "Lunacy and the Full Moon" points to a study where nurses who believed in lunar influences wrote more notes about patients’ peculiar behavior than nurses who didn't believe.

Findings From Further Analysis

Psychologists James Rotton and Ivan Kelly conducted a meta-analysis of 37 studies and concluded the lunar cycle accounted for no more than 1 percent of the variance in activities usually termed lunacy. Their work was published in 1985 in the journal "Psychological Bulletin." Kelly is quoted in a February 2004 article in "National Geographic News" as saying he feels the case for lunar effects has not been made.

About the Author

Based in Southern California, A.T. Gardner has spent more than two decades writing articles, educational materials, video scripts and other content for corporations and organizations including The Walt Disney Company, TRW, Nissan and the Centers for Disease Control and Prevention (CDC). He has a bachelor's degree in communications.